From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>,
linux-fbdev@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
dri-devel@lists.freedesktop.org,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: Re: [PATCH 5/5] backlight: led_bl: rewrite led_bl_parse_levels()
Date: Tue, 21 Apr 2020 14:26:41 +0300 [thread overview]
Message-ID: <0c7d02aa-db51-1c6f-e126-88472db4345b@ti.com> (raw)
In-Reply-To: <20200421104812.kgsdgv2r7bu7iqhe@holly.lan>
On 21/04/2020 13:48, Daniel Thompson wrote:
> On Tue, Apr 21, 2020 at 08:52:02AM +0300, Tomi Valkeinen wrote:
>> On 20/04/2020 19:01, Daniel Thompson wrote:
>>> On Fri, Apr 17, 2020 at 02:33:12PM +0300, Tomi Valkeinen wrote:
>>>> led_bl_parse_levels() is rather difficult to follow. Rewrite it with a
>>>> more obvious code flow.
>>>
>>> ... that introduces new behaviour.
>>>
>>> There's a couple of new behaviours here but the one that particular
>>> attracted my attention is the disregarding the "default-brightness-level" if
>>> there is no table. That looks like a bug to me.
>>
>> I think the previous behavior was a (minor) bug: how can there be default
>> brightness level if there are no brightness levels?
>
> I don't think this was a bug.
>
> If there is no brightness table then backlight will adopt a 1:1 mapping
> versus the underlying LED meaning the concept of default brightness
> applies equally well whether or not a brightness table is supplied.
>
>
>> The led-backlight.txt is
>> a bit lacking (another thing to improve...) but led-backlight mimics
>> pwm-backlight, and pwm-backlight.txt says
>>
>> default-brightness-level: The default brightness level (index into the array
>> defined by the "brightness-levels" property)
>
> I think this implies we should improve the binding documentation!
>
> The parenthetic text's main purpose is to make clear which scale should
> be used when interpreting the default brightness. Just because the scale
> is 1:1 doesn't render it meaningless.
If I read pwm_bl.c right, that's not how the code works. If pwm_bl has no 'brightness-levels', then
'default-brightness-level' is ignored. Which matches the binding documentation.
What you suggest makes sense, though, so I can adjust this patch to make led_bl behave like that.
Tomi
--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-04-21 11:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-17 11:33 [PATCH 1/5] backlight: led_bl: fix cosmetic issues Tomi Valkeinen
2020-04-17 11:33 ` [PATCH 2/5] backlight: led_bl: drop useless NULL initialization Tomi Valkeinen
2020-04-20 15:29 ` Daniel Thompson
2020-04-17 11:33 ` [PATCH 3/5] backlight: led_bl: add led_access locking Tomi Valkeinen
2020-04-20 15:45 ` Daniel Thompson
2020-04-17 11:33 ` [PATCH 4/5] backlight: led_bl: fix led -> backlight brightness mapping Tomi Valkeinen
2020-04-20 15:55 ` Daniel Thompson
2020-04-21 5:57 ` Tomi Valkeinen
2020-04-17 11:33 ` [PATCH 5/5] backlight: led_bl: rewrite led_bl_parse_levels() Tomi Valkeinen
2020-04-20 16:01 ` Daniel Thompson
2020-04-21 5:52 ` Tomi Valkeinen
2020-04-21 10:48 ` Daniel Thompson
2020-04-21 11:26 ` Tomi Valkeinen [this message]
2020-04-21 11:53 ` Tomi Valkeinen
2020-04-20 15:29 ` [PATCH 1/5] backlight: led_bl: fix cosmetic issues Daniel Thompson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0c7d02aa-db51-1c6f-e126-88472db4345b@ti.com \
--to=tomi.valkeinen@ti.com \
--cc=b.zolnierkie@samsung.com \
--cc=daniel.thompson@linaro.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=jingoohan1@gmail.com \
--cc=lee.jones@linaro.org \
--cc=linux-fbdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).